Surfacing device



(Nov. 2, 1937. o, w fic- 2,097,806

SURFACING DEVICE 'Filed Nov. 23, 1936 2 shee'ts-sneet INVENTOR. ORRiN WEIDRICH ATTORNEY Nov. '2, 1937. E H 2,o97,so6

SU-RFAC ING DEVI CE Filed Nov; 23, 1936 v 2 Sheets-Sheef 2 52 V INVENTOR.

ORR\N WEI DRCH I ATroRNEY.

Patented Nov. 2, 1937 UNITED STATES PATENTIOFFICE SURFACING DEVICE Or-in Weidrich, Kcnmore, N. Y. Application November 23, 1936, Serial No. 112.379

The present invention relates to improvements in surfacing devices and is particularly directed to the manner by which a work engaging abrasive is supported for movement over a surface to be finished. More specifically, the invention pertains to improvements in the Component parts of the abrasive supporting member including an abrading disc adapted for use in conjunction with a surfacing device and a method of making such 1 discs. p

It has been a desirable practice in abrasive surfacing devices of the 'disc type to cover the driven supporting member with a layer of resilient material, over which the abrasive disc is secured so that the abrasive will follow irregularities in the work surface and provide a more satisfactory finish to the material under treat-'- ment. The yieldable' layer employed in such devices must necessarily be pliable enough to permit a certain amount ot yielding of the abrasive v disc. When 'such characteristics are present, the peripheral portions of the yieldable layer have an unfortunate tendency'to yield more than the portion's near the center of the disc so that the less stable backing near the perlphery results in unsatisfactory .eutting by that portion of the disc. The tendencyof the peripheral y portion of the pliable layer to yield more along the outer edge probably results from the fact that a unit area of the resilient material at the periphery is not laterally supported on all sides as is the case with the more centrally located unit areas of the layer. Whatever may be the cause, the peripheral edge is known to give away to provide unatisfactory abrading by that portion of the disc. It is themelore an object of the present invention to provide means for reinforcing the peripheral portion of the yieldable layer used in con-' nection with disc type surfacing devices so that sive disc and the driven support with stabilizing means which will permit portions of the resilient p layer to engage the disc and thereby provide traction to drive the disc over a work surface. 50 A further object of the invention is to provide an inexpensive abrasive disc' of 'conical shape by a method of manufacture 'whichflnvolves a minimum of steps." i V --Other and further'features and objects o! the i( iii lnvention wilibe more apparent tothose skilled in the art upon a consideration of the accompanying drawings and the following description wherein an exemplary embodiment of the invention is disclosed.

In the drawings: Figure 1 is a side elevation of a surfacing device showing a machine for supporting and driving an abrasive disc of the conical type; I Figure 2 is a plan View of the bottom of the machine shown in Figure 1; 10 v Figure 3 is a sectional view of one type of an abrasive supporting member showing a reiniorcing disc and an abrasive disc in separated, 'mountable positions for the purpose of clearness; 15

Figura 4 is an enlarged sectional view of a portion of the abrasive supporting assembly;

Figure 5 is a view of a. flat abrasive disc shown in full lines with a. segment removed while the dotted lines indicate another disc with a segment removed and positioned under the abrasive disc; Figure 6 is a top`view of a conical shaped abrasive disc formed from the flat discs shown in Figure 5. 4 5

Figure 1 'a machine adapted to guide and drive ani abrasive' element I!) over a work surface indicated generally at ll. For the purpose of properly supporting and driving a conical shaped 30 abrasive disc. a triangular shaped plate |2 provides a frame for mounting a. driving device l3 and the rotatable abrasive support o. A pair of caster type rollers M secured to the under side of the plate l2 supports the driving device 35 !3 and the i'rame |2 at the proper angle to permit the conica shaped abrasive element u to engage the surface to be abraded. The driving device I: maybe oi any well-known type such as an electric motor and is preferably mounted 40 in a vertical manner with respect to the supporting plate i! so that a pulley ll mounted on the shait of the motor will be aligned for belt connection' with a pulley a, `carried by a stub shaft !9 of the abrasive supporting member o. 4

The upper end o't the shaft IS is journaled' ina hearing 2 I so as to permit the abrasive supporting member to be rotated by means of a belt 22 L operating .oven 'the pulleys l'l and s. I

-A debris collecting device 23 may be assoc'iated with the rotatable disc to carry away any; finely divided material accumulated from thej' work operated upon.. A tube 24, moreclearly 'fl shown in Figura 2, is-provided to extend into the proximity ofthe abrasive disc and to extendfl gg rearwardly and upwardly through the plate-like I'rame I 2 and is attached 'thereto by means of an appropriate collar 26 or similar means. Any suitable dust collection fan (not shown) may be provided at the top of the tube 23 to draw the abraded material from the vicinity of the grinding element.

The component parts of the abrading member are shown in a more detailed manner in Figure 3 and consist essentially of an abrasive disc 21, a reinforcing member 28 and a rotatable support 29. The supporting member 29 is provided with an internally threaded hub 3l which is adapted to be screwed over the end of the stub shaft s in such a manner as to cause the supporting member 29 to be rotated thereby. The supporting member may be formed of any rigid material such as a metal alloy having a conical shaped outer surface 32. The inner portion of the supporting member is preferably formed in a concave manner to reduce the weight of the assembly.

Any resilient material may be employed to provide a yieldable layer 33 on the conical surface 32 of the supporting member. sponge' rubber has been found unusually satisfactory for this purpose and the layer 33 of such material is adhesively secured to the supporting member by means of any well-known cement.

If .an abrasive disc 21 is secured over the re'- silient layer 33, and the supporting member is moved over a work surface in a manner as illustrated in Figure 1, grinding may be'accomplished. The rubber layer 33, in addition to permitting the abrasive disc to yield and follow any irregularities in the work surface also grips the inner surface 34 of the abrasive disc to impart driving traction thereto. In such an arrangement, the periphera edge of the disc as hereinabove described has a tendency to yield more than other portions of the resilient layer with the result that uneven abrading is accomplished by such an arrangement.

4 All the advantages derived from the use of the yieldable layer may be retained and the above indicated disadvantages overcome by positioning 'the reinforcing member 28 over the resilient layer 33 and thereafter securing theabrasive disc 21 over the reinforcing disc. The reinforcement consists of a conical shapedsheet metal disc which is adapted to fit closely over the conical surface of thesupporting member. The reinforcing disc should be formed of some reiatively thin sheet material such as spring steel approximately one siXt'y-fourth (1/64) of an inch in ithickness to provide the disc with characteristics of flexibility and at the same time provide rigidity to the same, in order that the outer peripheral edge will be prevented from bending excessively.

The abrasive disc 21 of conical shape is adapted to fit over the reinforcing member 28 and. both discs may be removaby secured to the supporting member 29 by means of a screw 36 which passes through an opening 31 in the abrasive disc and a similarly positioned aperture 38 in the reinforcing member, to engage the threaded opemng 38 in theapex of the supporting member. A Washer 40 should be provided to fit over a small area ofthe abrasive disc so that the two discs may be clamped to the supporting member with suflicient pressure to partially embed the reinforcing .disc

in the yieldable layer 33 as hereinafter described. i

In order that the yieldable layer will still be permitted to engage the inner surface 34 of the abrasive disc for driving the same, a number of reiatively large openings 4I may be provided in the reinforcing memben These holes may be arranged in any pattern so long as the rigidity of the peripheral edge 42 is not reduced enough to cause the edge to give away and prmita similar portion of the abrasive disc to yield disproportionately. When the abrasive disc 21 and such a reinforcing member 28 are fixed to the supporting member 29 with sufficient pressure'by means of the screw 36, portions of the yieldable layer will project through the openings 41 and grip the inner surface 34 of the abrasive disc in a manner as shown in Figur'e 4 and provide driving traction to move the abrasive disc over a work surface.

It is to be noted that the reinforcing disc 28 is formed to have a diameter substantially equal to that of the abrasive disc 21. such an assembly may therefore be moved adjacent a vertical projection in the work surface, as for example, the

baseboard of a floor, and abrading will be accomplished by the peripheral edge of the disc to provide even cutting and uniform surfacing of the floor in the immediate proximity of the baseboard.

The abrasive discs employed in surfacing machines of the present type must be renewed at reiatively short intervals, particularly when varnish and the like is being removed from oors, so that it is not economicaliy advisable to 'employ expensive abrasive discs such'as the well known type wherein hydroiyzed cellulose or vulcanized fiber is used as the backing. Since the herenabo've described resilient layer provides driving traction by engaging the inner surface of the abrasive disc, a more inexpensive disc may be used in connection with such a surfacing device.

A disc for suchmachines may be manufactured in a. simplified manner by cutting sheet abrasive material into the form of a flat disc 44 a's shown by the full lines in Figure 5, with a segment indicated at 43 removed. Then, by positioning the radially extending edges 46 and 41 of the abrasive disc adjacent each other, a conical shaped abrasive will be formed, having a slope as determined by the angle of the segment removed. A similarly cut blank disc 48 of uncoated backing material, indicated by the dotted lines in Figure 5, is arranged in a staggered relation with respect to the abrasive disc 44. When the radially extending edges 5l and 52 of the disc 48 a're joined, another conical disc will be formed. A finished conical shaped disc, such as shown in Figure 6, may then be formed by adhesiveiy securing the disc 48 to the under side of the disc 44 'by means of any well-known adhesive.such as glue.

It may be desirable in some cases to further improve the gripping action on the inner surface of the abrasive disc. such a result may be accomplished by placing two abrasive discs 44 in a back to back relaton to form a double faced conical shaped abrasive disc. The inner abrasive surface will then provide a greater frictional surface for the portions of the yieldable layer projecting through the openings 44 of the reinforcing member when such a disc is attached to the rotatable supporting member 29. A disc of `th latter type. provides an added advantage -of permitting the same to be reversed on the .and the worn abrasive face will still provide a aoozsoo I embodiments of the inventionhave been disclosed, it is further apparent thatmodifications may be made by those skilled in the art. such modiflcations may be made without departing from the spirit and scope of the invention as set forth in the appended claims:

I claim:

1. A rotatable surfacing device comprising a conical shaped supporting member, a layer of resilient material covering the conical surface of said supporting member, a conical shaped reinforcing disc adapted to fit over said resilient layer, a conical shaped abrasive disc arranged over said reinforcing member and means for removably securing said abrasive and said reinforcing disc to said supporting member at the apices of said cone surfaces.

2. A rotatable surfacing device comprising a supporting member having a conical shaped face directed toward a. work surface, a layer of yieldable material covering the conical face of said supporting member, a perforated reinforcing disc adapted to flt over said yieldable layer, a conical shaped abrasive disc arranged over said reinforcing disc and means for removably securing' said discs to said supporting member at the apices of said cone surfaces with sufllcient pressure to cause portions of said yieldable layer to project through the perforations of said reinforcing discs and engage the inner surface of said abrasive disc.

3. A rotatable surfacing device comprising a conical shaped driven supporting member, a layer of sponge rubber -covering the conical surface of said supporting member, a conical shaped sheet metal disc having a plurality of openings A therethrough adapted to fit over said rubber layer,

a conical shaped abrasive disc arranged over said metal disc and means for clamping said abrasive disc and said metal to said supporting member with sumcient pressure to cause portions of said rubber to project through the openings in said metal disc and drive said abrasive disc by'friction engagement therewith.

4. A rotatable surfacing device comprising a circular shaped supporting member, a layer ot yieldable material &fixed to the surface of said supporting member, a reinforcing disc having a plurality of openings therethrough adapted to be positioned over said yieldabe layer, an abrasive disc adapted to be mounted over said reinforcing disc, and means positioned centrally of said discs for securing said discs to said supporting member, said means being capable of exerting sufllcient pressure on said reinforcing disc- ,to cause portions of said yieldable material to protrude through said openings whereby the protruding portion may engage said abrasive disc.

5. The method of making a conical shaped abrasive disc which comprises shaping flat sheet abrasive material into the form of a disc, removing a segment from the flat disc, joining the radially extending edges of the disc to shape the disc in the form of a cone, and adhesively securing the conical shaped `abrasive disc to a similarly formed blank cone in a juxtaposed -manner with the radially extending joined edges of the two conical shaped discs circumferentially spaced with respect to each other.

6. The method of making a conical shaped abrasive disc which comprises shaping flat sheet abrasive material into the form of a disc, removing a segment from the flat disc, joining the radially extending edges of the disc to shape the disc in the form of a. cone. and adhesively securing the conical shaped abrasive disc to a simiiarly formed blank cone in a juxtaposed manner with the radally extending Joined edges of the two conical shaped discs staggered with respect to each other.

7. An abrasive article comprising a conical shaped disc having a layer of abrasive particles Secured to the convex surface thereof, said disc being split and having a radially extending joint, a conical shaped disc having the convex surface thereof ,adhesively Secured to the concave surface of said abrasive disc to 'provide a hacking therefor and reinforcement of said radially extending joint.

8. An abrasive article comprising a conical shaped disc having abrasive particles Secured to the convex surface thereof, said disc being split and having a radially extending joint. a second conical shaped disc having abrasive particles secured to the concave surface thereof, the convex surface of said second mentioned disc being adhesiveLv secured to the concave surface of said first mentioned disc to provide a hacking therefor and reinforcement of said radially extendin Joint.

ORRIN WEIDRICH. 

